With an unjust war, it seems to me that the state would be killing innocent people. Therefore, an unjust war is on par with the state mandating abortion, which is worse than the state allowing abortion.
I think this is a pretty good argument. Not unanswerable, maybe; state-mandated abortion and unjust war are significantly different evils. But the idea that directly killing an innocent person is objectively worse than immediate material cooperation in that killing seems plausible to me, and I can see the reason to extend that to directly killing one innocent person being objectively worse than immediate material cooperation in another killing.
Jcecil3 goes on:
Therefore, I could be wrong, but it seems to me that the most moral choice is to vote for John Kerry....
Which is quite a different argument.
It seems to me you can extend the "unjust war is worse than permissive abortion laws" claim to a "George Bush is worse than John Kerry" claim in one of three ways.
You can say Bush has prosecuted an unjust war, and therefore is necessarily worse than Kerry, who hasn't; or you can say Bush will prosecute an unjust war, and Kerry won't. I don't think either of these is necessarily sound. As someone who prefers virtuous candidates, I can see why someone who starts an unjust war might be seen as unfit for office, but that by itself doesn't mean everyone who hasn't started an unjust war is necessarily more fit. As for what will happen, it seems to me Kerry's aggressive push of legal abortion through birth, worldwide and in perpetuity is far more certain than either another war under Bush or the absence of a war under Kerry.
A third way of arguing that Bush is worse than Kerry because unjust war is worse than permissive abortion laws, what might be called an operational argument, is that the very fact of having, and even reelecting, a president who has caused an unjust war is worse for the common good than having, or electing, a president who loves loves loves to immediately materially cooperate with abortions through birth, worldwide and in perpetuity. I don't know that this can be strictly proven, but I think it is a defensible personal judgment. (Defensible meaning consonant with reason and faith, not correct, persuasive, or even highly probable.)
Still, in my personal judgment (which I of course consider defensible, but what do I know), Kerry's own position on government-funded abortions and fetal stem cell research constitutes the state killing innocent people, so even accepting Jcecil3's first principle (and his judgment of the war) without reservations leaves no clear choice between the two candidates.